1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device and method for fabricating the same, and more particularly, to a seal pattern included in an LCD device.
2. Discussion of the Related Art
Among flat panel display devices, liquid crystal display (LCD) devices have many advantages, such as a low energy consumption due to a low operating voltage thereof and a high applicability for portable appliances, etc. Therefore, LCD devices are widely used in a variety of fields such as monitors for notebook computers, spaceships, aircraft, etc.
Generally, an LCD device includes upper and lower substrates facing each other, a liquid crystal layer between the upper and lower substrates, and a seal material surrounding the liquid crystal layer to bond the upper and lower substrates together.
A method for fabricating an LCD device according to the related art will be explained with reference to the accompanying drawings. FIGS. 1A to 1D are schematic perspective views illustrating a method for fabricating an LCD device according to the related art.
Referring to FIG. 1A, a lower substrate 10 and an upper substrate 30 are first prepared. Although not shown, the lower substrate 10 is formed with thin-film transistors and pixel electrodes, and the upper substrate 30 is formed with a black matrix layer, a color filter layer, and a common electrode.
Referring to FIG. 1B, a seal pattern 50 is then coated on the lower substrate 10. The seal pattern 50 has an injection port to inject liquid crystal into a space between the lower substrate 10 and the upper substrate 30 after bonding the substrates 10 and 30.
Referring to FIGS. 1C and 1D, the lower substrate 10 and upper substrate 30 are bonded together using the seal pattern 50. Thereafter, the bonded lower and upper substrates 10 and 30 are cut into a plurality of unit cells, as illustrated in FIG. 1D. Each unit cell is configured in such a manner that a side x of the lower substrate 10 is longer than the corresponding side y of the upper substrate 30 to expose a pad portion formed on the lower substrate 10 for the connection of a drive circuit. In FIG. 1D, the pad portion of the lower substrate 10 is marked with oblique lines. In order to expose the pad portion of the lower substrate 10, it is necessary to perform a primary cutting process for cutting both the lower substrate 10 and upper substrate 30 along the line A-A of FIG. 1C and a secondary cutting process for cutting a portion of the upper substrate 30 along the line B-B of FIG. 1C.
Although not shown, after the cutting processes, liquid crystal is injected into the space between the lower substrate 10 and the upper substrate 30 through the injection port of the seal pattern 50 formed at each unit cell. After completing the injection of the liquid crystal, the injection port of the seal pattern 50 is sealed to complete the fabrication process of the LCD device.
The method for fabricating an LCD device according to the related art has, however, the following problems.
In order to increase productivity, it is beneficial to increase the number of unit cells to be formed on a single substrate. As the number of unit cells increases, the distance between the unit cells becomes smaller and the distance between the seal patterns formed unit cells becomes reduced. Because of the reduced distance between the seal patterns, the seal pattern in one unit cell spreads out to adjacent unit cells during the bonding process, thereby decreasing efficiency in the cutting process. This problem will be described in more detail with reference to FIGS. 2A and 2B.
Referring to FIGS. 2A and 2B, the circle “C” illustrates the seal pattern 50 spread out to a neighboring unit cell when the lower substrate 10 and upper substrate 30 are bonded to each other. As described above, after the boding process, a cutting process is performed along the line B-B of FIG. 2A to remove a portion 30a of the upper substrate 30 of the unit cell to expose the pad portions of the lower substrate 10. However, the seal pattern 50 spread out to a neighboring unit cell may cause a failure in the cutting process.